string/strtok.c

   1 /* Copyright (C) 1991,1996,1997,1999,2000,2001,2007
   2    Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <string.h>
  21
  22
  23 static char *olds;
  24
  25 #undef strtok
  26
  27 /* Parse S into tokens separated by characters in DELIM.
  28    If S is NULL, the last string strtok() was called with is
  29    used.  For example:
  30         char s[] = "-abc-=-def";
  31         x = strtok(s, "-");             // x = "abc"
  32         x = strtok(NULL, "-=");         // x = "def"
  33         x = strtok(NULL, "=");          // x = NULL
  34                 // s = "abc\0=-def\0"
  35 */
  36 char *
  37 strtok (s, delim)
  38      char *s;
  39      const char *delim;
  40 {
  41   char *token;
  42
  43   if (s == NULL)
  44     s = olds;
  45
  46   /* Scan leading delimiters.  */
  47   s += strspn (s, delim);
  48   if (*s == '\0')
  49     {
  50       olds = s;
  51       return NULL;
  52     }
  53
  54   /* Find the end of the token.  */
  55   token = s;
  56   s = strpbrk (token, delim);
  57   if (s == NULL)
  58     /* This token finishes the string.  */
  59     olds = __rawmemchr (token, '\0');
  60   else
  61     {
  62       /* Terminate the token and make OLDS point past it.  */
  63       *s = '\0';
  64       olds = s + 1;
  65     }
  66   return token;
  67 }